The present invention provides methods for the delivery of a therapeutic agent to lymph nodes or other targeted tissues via the bladder. In particular, the methods of the invention provide the use of microparticles or nanoparticles comprising a biocompatible polymer and the therapeutic agent where the microparticles or nanoparticles are non-invasively instilled into the bladder and subsequently localized to the lymph node whereupon the therapeutic agent is released from the polymer matrix. The present invention further relates to methods of modulating immune response and methods of systemically administering a therapeutic using bladder delivery of microparticles.
Administration via the bladder has been used as a route of delivery for local treatments of bladder cancer, but no examples have been disclosed of molecular uptake from the bladder where the molecule was transported to another tissues. For example, one study that used replication-deficient adenovirus to transfect bladder cells with the beta-galactosidase and p53 genese found no evidence of cellular transfection in the liver, lung, or heart of treated animals (Werthman, P. E., K. E. Drazan, J. T. Rosenthal, R. Khalili, and A. Shaked, Adenoviral-p53 gene transfer to orthotopic and peritoneal murine bladder cancer. Journal of Urology, 1996. 155(2): p. 753-756). It has also been shown that when 125I-interferon-xcex1 protein encapsulated in phosphtidylcholine/phosphatidyserine liposomes was instilled into C57BL/6 mice, systemic absorption was negligible, as evidenced by examination of amount of radiation in the kidney, spleen, liver, and lungs (Frangos, D. N., J. J. Killion, D. Fan, R. Fishbeck, A. C. von Eschenbach, and I. J. Fidler, The development of liposomes containing interferon alpha for the intravesical therapy of human superficial bladder cancer. Journal of Urology, 1990. 143(6): p. 1252-6). Finally, systemic absorption of doxorubicin following intravesical administration is minimal (Jacobi, G. H. and K. H. Kurth, Studies on the intravesical action of topically administered G3Hxe2x80x94doxorubicin hydrochloride in men: plasma uptake and tumor penetration. J Urol, 1980. 124(1) 34-7). Thus, it has been demonstrated in these studies that drugs, proteins, and genes remain localized to the bladder following bladder instillation.
There are currently many different routes that can be used to administer drugs, proteins, and genes systemically. Each has unique advantages and disadvantages, and each is useful in certain situations; there is no one xe2x80x9cbestxe2x80x9d method for delivering molecules systemically. For example, intravenous injection of the compound allows 100% of the dose to be transferred to the patient and the compound is rapidly carried throughout the body through the bloodstream. However, injection with needles carries the possibility of infection, as one of the body""s primary barriers to infection is breached; this is especially a problem when the needle is not sterile. Furthermore, injections can be painful and most often must be performed by trained medical staff, which increases the cost of the procedure. Also, once the molecule is injected into the blood, serum proteins can rapidly bind to and inactivate it; many molecules thus have short serum half-lives.
Oral administration is promising in many cases, as the patient can self-administer the dose and the administered molecules can be delivered to specific areas of the digestive tract. For example, the gut-associated lymphoid tissue (GALT) is an inviting area of the gut for the administration of vaccines (Jones, D. H., J. C. Clegg, and G. H. Farrar, Oral delivery of micro-encapsulated DNA vaccines. Developments in Biological Standardization, 1998. 92: p. 149-55). Molecules delivered orally must pass through the acidic environment of the stomach, though, which often causes substantial degradation of the administered dose. Unprotected xe2x80x9cnakedxe2x80x9d DNA, for instance, is totally inactivated in the stomach. Carriers such as chitosan and poly(lactic-co-glycolic acid) (PLGA) have been used to protect the molecular load from the hard environment of the stomach (Jones, D. H., J. C. Clegg, and G. H. Farrar, Oral delivery of micro-encapsulated DNA vaccines. Developments in Biological Standardization, 1998. 92: p. 149-55; Roy, K., H. Q. Mao, S. K. Huang, and K. W. Leong, Oral gene delivery with chitosanxe2x80x94DNA nanoparticles generates immunologic protection in a murine model of peanut allergy. Nature Medicine, 1999. 5(4): p. 387-91; Kofler, N., C. Ruedl, C. Rieser, G. Wick, and H. Wolf, Oral immunization with poly-(D,L-lactide-co-glycolide) and poly-(L-lactic acid) microspheres containing pneumotropic bacterial antigens. International Archives of Allergy and Immunology, 1997. 113(4): p. 424-31). Following passage through the stomach, the molecules must be taken up by various areas of the intestines, which is inefficient for many compounds (sources). Improvements in the uptake have been made in many cases. In one example, 0.5% of administered nanospheres were taken up, which was improved to 23% by the addition of lectin receptors to the nanospheres. After uptake by the gut, most molecules will travel to the liver and will be subjected to degradative enzymes in this first-pass hepatic metabolism. In most case, the majority of the administered dose is thus lost.
Advantages and disadvantages of a variety of application methods for systemic delivery of a therapeutic agent are tabulated in Table I. A number of application methods are known in the art and include intramuscular, oral, intravenous, intraperitoneal, subcutaneous, intranasal, pulmonary, transdermal, intradermal, buccal, sublingual, vaginal and rectal. Each common method of administration has disadvantages including low uptake of therapeutic agent, poor systematic absorption of the therapeutic agent, plasma protein bonding to the therapeutic agent, therapeutic agent degradation in the gastrointestinal tact or in the liver, difficult or painful administration procedures and the like. Other methods of delivery of a therapeutic agent are still needed which have therapeutic agent uptake and high systemic delivery.
In bladder instillation studies to date it has been demonstrated that instillation of molecules and particles do not lead to systemic uptake; the prior art teaches that bladder instillation of a therapeutic is only suitable for treatment for locally-occurring disorders such as bladder cancer. Molecules which have been instilled in the bladder including low molecular weight chemotherapeutic drugs like taxol, proteins such as interferon-xcex1, viruses such as the adenovirus, and nonviral gene-containing liposomes are not transfected to other internal organs such as lung, spleen, kidney, liver or the like.
The present invention provides methods of administering a therapeutic agent to the lymph nodes, systemically delivering a therapeutic agent and modulating immune response by instilling microparticles or nanoparticles in the bladder. The methods of the invention use microparticles and nanoparticles which are taken up by the bladder, exit the bladder via lymphatics and are transported to the lymph nodes. Any therapeutic agent compatible with a polymer suitable for use in microspheres and nanospheres suitable for use in the methods of the invention may be administered to the lymph node or be distributed systemically by the methods of the invention. Preferred therapeutics include drugs, pro-drugs, proteins and genes.
The present invention provides microparticles and nanoparticles comprising a therapeutic agent and a biodegradable poly(phosphoester) that are taken up by the bladder tissue, are transported through lymphatic vessels, and are deposited in the lymph nodes within three hours of instillation. This transport occurs with high efficiency; more than 90% of the administered dose remains in the animal, which compares favorably with conventional oral administration, where often 10% or less of the administered dose is taken up. We have examined the mechanism of this transport and have shown that the particles are taken up inside vesicles in epithelial cells, which aids their transport through the epithelial layer to the draining lymphatics.
We have fabricated nanometer-sized spheres (nanospheres) which are taken up into the bladder wall following noninvasive bladder instillation. More than 90% of the instilled dose remains in the animal. After a short time inside the bladder wall, these nanospheres exit the bladder via the lymphatics and are transported to the lymph nodes. Drugs, proteins, and genes may be delivered from the nanospheres to the surrounding cells. Thus, the bladder represents a new route of administration to give a systemic response to the administered molecules.
In one aspect, the present invention provides a method of delivering a therapeutic agent to a patient""s lymph node comprising
providing a microparticle or nanoparticle composition comprising at least one biocompatible polymer and at least one therapeutic agent;
instilling at least one microparticle or nanoparticle into a patient""s bladder such that at least a portion of the instilled microparticle or nanoparticles are localized to the lymph nodes; and
releasing at least a portion of the therapeutic agent from the microparticle into the lymph node.
The present invention also relates to methods for modulating immune response comprising the steps of:
instilling at least one microparticle with one or more encapsulated therapeutic agents capable of modulating immune response to the bladder of a patient, transporting the microparticles to the lymph node and releasing the encapsulated therapeutic agent to modulate the immune response of the patient.
The present invention further provides a method for systemic delivery of a therapeutic agent to a patient, the method comprising the steps of:
providing a microparticle or nanoparticle composition comprising at least one biocompatible instilling at least one microparticle comprising a therapeutic agent into a patient""s bladder under conditions conducive to the transport of at least a portion of the microparticles across the epithelial layer of the bladder; and
releasing at least a portion of the therapeutic agent from the microparticle such that the therapeutic agent is distributed systemically.